I've been having trouble tuning my 8 inch tom. Finally I pull the heads off completely and inspect the shell. Bearing edges look great. Then I hold the drum an arm length away, and it doesn't look quite perfectly round to me. I measured the width of the drum at each lug, and I'm seeing what appears to be about 1/4" difference at some spots. I put the reso head back on, but turn it 90 degrees first - it's snug, too snug to be normal, the edges of the head touch the bearing edges. I put it back on how it came from the factory, it fits fin. Turn the head around the drum - gets about 90 degrees, and stops moving freely. Looks like my 8" is way out of round. :(